Normal moveout refers to the horizontal distance that a wave travels before returning to a point of origin. It is a critical parameter in the field of seismic interpretation, used in determining subsurface velocities, and ultimately, building accurate images of subsurface structures. Some synonyms for normal moveout include wave travel distance, time-depth conversion, and time-distance relationship. Other related terms include reflection wave travel time, velocity analysis, and time delay. The ability to accurately measure normal moveout is essential in the oil and gas industry, where it is used in determining drilling targets, evaluating reservoir properties, and predicting production rates.